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Add value range analyzing of Add and Sub.

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Understand that mul %x, 1 = %x.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58069 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2008-10-24 04:00:26 +00:00
parent 06587497dc
commit 79cce5c51b
1 changed files with 73 additions and 9 deletions
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82
lib/Transforms/Scalar/PredicateSimplifier.cpp
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@ -1938,6 +1938,7 @@ namespace {
assert(!Ty->isFPOrFPVector() && "Float in work queue!");
Constant *Zero = Constant::getNullValue(Ty);
Constant *One = ConstantInt::get(Ty, 1);
ConstantInt *AllOnes = ConstantInt::getAllOnesValue(Ty);
switch (Opcode) {
@ -1945,19 +1946,73 @@ namespace {
case Instruction::LShr:
case Instruction::AShr:
case Instruction::Shl:
if (Op1 == Zero) {
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
return;
}
break;
case Instruction::Sub:
if (Op1 == Zero) {
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
return;
}
if (ConstantInt *CI0 = dyn_cast<ConstantInt>(Op0)) {
unsigned n_ci0 = VN.getOrInsertVN(Op1, Top);
ConstantRange CR = VR.range(n_ci0, Top);
if (!CR.isFullSet()) {
CR.subtract(CI0->getValue());
unsigned n_bo = VN.getOrInsertVN(BO, Top);
VR.applyRange(n_bo, CR, Top, this);
return;
}
}
if (ConstantInt *CI1 = dyn_cast<ConstantInt>(Op1)) {
unsigned n_ci1 = VN.getOrInsertVN(Op0, Top);
ConstantRange CR = VR.range(n_ci1, Top);
if (!CR.isFullSet()) {
CR.subtract(CI1->getValue());
unsigned n_bo = VN.getOrInsertVN(BO, Top);
VR.applyRange(n_bo, CR, Top, this);
return;
}
}
break;
case Instruction::Or:
if (Op0 == AllOnes || Op1 == AllOnes) {
add(BO, AllOnes, ICmpInst::ICMP_EQ, NewContext);
return;
} // fall-through
case Instruction::Xor:
}
if (Op0 == Zero) {
add(BO, Op1, ICmpInst::ICMP_EQ, NewContext);
return;
} else if (Op1 == Zero) {
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
return;
}
break;
case Instruction::Add:
if (ConstantInt *CI0 = dyn_cast<ConstantInt>(Op0)) {
unsigned n_ci0 = VN.getOrInsertVN(Op1, Top);
ConstantRange CR = VR.range(n_ci0, Top);
if (!CR.isFullSet()) {
CR.subtract(-CI0->getValue());
unsigned n_bo = VN.getOrInsertVN(BO, Top);
VR.applyRange(n_bo, CR, Top, this);
return;
}
}
if (ConstantInt *CI1 = dyn_cast<ConstantInt>(Op1)) {
unsigned n_ci1 = VN.getOrInsertVN(Op0, Top);
ConstantRange CR = VR.range(n_ci1, Top);
if (!CR.isFullSet()) {
CR.subtract(-CI1->getValue());
unsigned n_bo = VN.getOrInsertVN(BO, Top);
VR.applyRange(n_bo, CR, Top, this);
return;
}
}
// fall-through
case Instruction::Xor:
if (Op0 == Zero) {
add(BO, Op1, ICmpInst::ICMP_EQ, NewContext);
return;
@ -1974,19 +2029,30 @@ namespace {
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
return;
}
// fall-through
if (Op0 == Zero || Op1 == Zero) {
add(BO, Zero, ICmpInst::ICMP_EQ, NewContext);
return;
}
break;
case Instruction::Mul:
if (Op0 == Zero || Op1 == Zero) {
add(BO, Zero, ICmpInst::ICMP_EQ, NewContext);
return;
}
if (Op0 == One) {
add(BO, Op1, ICmpInst::ICMP_EQ, NewContext);
return;
} else if (Op1 == One) {
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
return;
}
break;
}
// "%x = add i32 %y, %z" and %x EQ %y then %z EQ 0
// "%x = add i32 %y, %z" and %x EQ %z then %y EQ 0
// "%x = shl i32 %y, %z" and %x EQ %y and %y NE 0 then %z EQ 0
// "%x = udiv i32 %y, %z" and %x EQ %y then %z EQ 1
// "%x = udiv i32 %y, %z" and %x EQ %y and %y NE 0 then %z EQ 1
Value *Known = Op0, *Unknown = Op1,
*TheBO = VN.canonicalize(BO, Top);
@ -2009,10 +2075,8 @@ namespace {
case Instruction::UDiv:
case Instruction::SDiv:
if (Unknown == Op1) break;
if (isRelatedBy(Known, Zero, ICmpInst::ICMP_NE)) {
Constant *One = ConstantInt::get(Ty, 1);
if (isRelatedBy(Known, Zero, ICmpInst::ICMP_NE))
add(Unknown, One, ICmpInst::ICMP_EQ, NewContext);
}
break;
}
}
@ -2488,7 +2552,7 @@ namespace {
void PredicateSimplifier::Forwards::visitLoadInst(LoadInst &LI) {
Value *Ptr = LI.getPointerOperand();
// avoid "load uint* null" -> null NE null.
// avoid "load i8* null" -> null NE null.
if (isa<Constant>(Ptr)) return;
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &LI);
@ -2624,8 +2688,8 @@ namespace {
if (!Op1->getValue().isAllOnesValue())
NextVal = ConstantInt::get(Op1->getValue()+1);
break;
}
if (NextVal) {
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &IC);
if (VRP.isRelatedBy(IC.getOperand(0), NextVal,